docs: def getArrays(self):
          """Return wavelength and flux arrays in user units.
  
          Returns
          -------
          wave : array_like
              Wavelength array in ``self.waveunits``.
  
          flux : array_like
              Flux array in ``self.fluxunits``.
              When necessary, ``self.primary_area`` is used for unit conversion.
  
          """
          if hasattr(self, 'primary_area'):
              area = self.primary_area
          else:
              area = None
  
          wave = self.GetWaveSet()
          flux = self(wave)
  
          flux = units.Photlam().Convert(
              wave, flux, self.fluxunits.name, area=area)
          wave = units.Angstrom().Convert(wave, self.waveunits.name)
  
          return wave, flux